//
// vsprintf.c
//
// Print formatting routines
//
// Copyright (C) 2002 Michael Ringgaard. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
// 3. Neither the name of the project nor the names of its contributors
//    may be used to endorse or promote products derived from this software
//    without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
// OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
// SUCH DAMAGE.
//

#include <stdio.h>

#define KERNEL
#ifdef KERNEL
#define NOFLOAT
#endif

#define ZEROPAD 1               // Pad with zero
#define SIGN    2               // Unsigned/signed long
#define PLUS    4               // Show plus
#define SPACE   8               // Space if plus
#define LEFT    16              // Left justified
#define SPECIAL 32              // 0x
#define LARGE   64              // Use 'ABCDEF' instead of 'abcdef'

#define is_digit(c) ((c) >= '0' && (c) <= '9')

static char *digits = "0123456789abcdefghijklmnopqrstuvwxyz";
static char *upper_digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";

typedef int size_t;

static size_t strnlen(const char *s, size_t count)
{
    const char *sc;
    for (sc = s; *sc != '\0' && count--; ++sc);
    return sc - s;
}

static int skip_atoi(const char **s)
{
    int i = 0;
    while (is_digit(**s)) i = i*10 + *((*s)++) - '0';
    return i;
}

static char *number(char *str, long num, int base, int size, int precision, int type)
{
    char c, sign, tmp[66];
    char *dig = digits;
    int i;

    if (type & LARGE)  dig = upper_digits;
    if (type & LEFT) type &= ~ZEROPAD;
    if (base < 2 || base > 36) return 0;

    c = (type & ZEROPAD) ? '0' : ' ';
    sign = 0;
    if (type & SIGN)
    {
        if (num < 0)
        {
            sign = '-';
            num = -num;
            size--;
        }
        else if (type & PLUS)
        {
            sign = '+';
            size--;
        }
        else if (type & SPACE)
        {
            sign = ' ';
            size--;
        }
    }

    if (type & SPECIAL)
    {
        if (base == 16)
        {
            size -= 2;
        }
        else if (base == 8)
        {
            size--;
        }
    }

    i = 0;

    if (num == 0)
    {
        tmp[i++] = '0';
    }
    else
    {
        while (num != 0)
        {
            tmp[i++] = dig[((unsigned long) num) % (unsigned) base];
            num = ((unsigned long) num) / (unsigned) base;
        }
    }

    if (i > precision) precision = i;
    size -= precision;
    if (!(type & (ZEROPAD | LEFT))) while (size-- > 0) *str++ = ' ';
    if (sign) *str++ = sign;

    if (type & SPECIAL)
    {
        if (base == 8)
        {
            *str++ = '0';
        }
        else if (base == 16)
        {
            *str++ = '0';
            *str++ = digits[33];
        }
    }

    if (!(type & LEFT)) while (size-- > 0) *str++ = c;
    while (i < precision--) *str++ = '0';
    while (i-- > 0) *str++ = tmp[i];
    while (size-- > 0) *str++ = ' ';

    return str;
}

static char *eaddr(char *str, unsigned char *addr, int size, int precision, int type)
{
    char tmp[24];
    char *dig = digits;
    int i, len;

    if (type & LARGE)  dig = upper_digits;
    len = 0;
    for (i = 0; i < 6; i++)
    {
        if (i != 0) tmp[len++] = ':';
        tmp[len++] = dig[addr[i] >> 4];
        tmp[len++] = dig[addr[i] & 0x0F];
    }

    if (!(type & LEFT)) while (len < size--) *str++ = ' ';
    for (i = 0; i < len; ++i) *str++ = tmp[i];
    while (len < size--) *str++ = ' ';

    return str;
}

static char *iaddr(char *str, unsigned char *addr, int size, int precision, int type)
{
    char tmp[24];
    int i, n, len;

    len = 0;
    for (i = 0; i < 4; i++)
    {
        if (i != 0) tmp[len++] = '.';
        n = addr[i];

        if (n == 0)
        {
            tmp[len++] = digits[0];
        }
        else
        {
            if (n >= 100)
            {
                tmp[len++] = digits[n / 100];
                n = n % 100;
                tmp[len++] = digits[n / 10];
                n = n % 10;
            }
            else if (n >= 10)
            {
                tmp[len++] = digits[n / 10];
                n = n % 10;
            }

            tmp[len++] = digits[n];
        }
    }

    if (!(type & LEFT)) while (len < size--) *str++ = ' ';
    for (i = 0; i < len; ++i) *str++ = tmp[i];
    while (len < size--) *str++ = ' ';

    return str;
}

int vsprintf(char *buf, const char *fmt, va_list args)
{
    int len;
    unsigned long num;
    int i, base;
    char *str;
    char *s;

    int flags;            // Flags to number()

    int field_width;      // Width of output field
    int precision;        // Min. # of digits for integers; max number of chars for from string
    int qualifier;        // 'h', 'l', or 'L' for integer fields

    for (str = buf; *fmt; fmt++)
    {
        if (*fmt != '%')
        {
            *str++ = *fmt;
            continue;
        }

        // Process flags
        flags = 0;
repeat:
        fmt++; // This also skips first '%'
        switch (*fmt)
        {
        case '-':
            flags |= LEFT;
            goto repeat;
        case '+':
            flags |= PLUS;
            goto repeat;
        case ' ':
            flags |= SPACE;
            goto repeat;
        case '#':
            flags |= SPECIAL;
            goto repeat;
        case '0':
            flags |= ZEROPAD;
            goto repeat;
        }

        // Get field width
        field_width = -1;
        if (is_digit(*fmt))
        {
            field_width = skip_atoi(&fmt);
        }
        else if (*fmt == '*')
        {
            fmt++;
            field_width = va_arg(args, int);
            if (field_width < 0)
            {
                field_width = -field_width;
                flags |= LEFT;
            }
        }

        // Get the precision
        precision = -1;
        if (*fmt == '.')
        {
            ++fmt;
            if (is_digit(*fmt))
            {
                precision = skip_atoi(&fmt);
            }
            else if (*fmt == '*')
            {
                ++fmt;
                precision = va_arg(args, int);
            }
            if (precision < 0) precision = 0;
        }

        // Get the conversion qualifier
        qualifier = -1;
        if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L')
        {
            qualifier = *fmt;
            fmt++;
        }

        // Default base
        base = 10;

        switch (*fmt)
        {
        case 'c':
            if (!(flags & LEFT)) while (--field_width > 0) *str++ = ' ';
            *str++ = (unsigned char) va_arg(args, int);
            while (--field_width > 0) *str++ = ' ';
            continue;

        case 's':
            s = va_arg(args, char *);
            if (!s) s = "<NULL>";
            len = strnlen(s, precision);
            if (!(flags & LEFT)) while (len < field_width--) *str++ = ' ';
            for (i = 0; i < len; ++i) *str++ = *s++;
            while (len < field_width--) *str++ = ' ';
            continue;

        case 'p':
            if (field_width == -1)
            {
                field_width = 2 * sizeof(void *);
                flags |= ZEROPAD;
            }
            str = number(str, (unsigned long) va_arg(args, void *), 16, field_width, precision, flags);
            continue;

        case 'n':
            if (qualifier == 'l')
            {
                long *ip = va_arg(args, long *);
                *ip = (str - buf);
            }
            else
            {
                int *ip = va_arg(args, int *);
                *ip = (str - buf);
            }
            continue;

        case 'A':
            flags |= LARGE;

        case 'a':
            if (qualifier == 'l')
            {
                str = eaddr(str, va_arg(args, unsigned char *), field_width, precision, flags);
            }
            else
            {
                str = iaddr(str, va_arg(args, unsigned char *), field_width, precision, flags);
            }
            continue;

            // Integer number formats - set up the flags and "break"
        case 'o':
            base = 8;
            break;

        case 'X':
            flags |= LARGE;

        case 'x':
            base = 16;
            break;

        case 'd':
        case 'i':
            flags |= SIGN;

        case 'u':
            break;

        default:
            if (*fmt != '%') *str++ = '%';
            if (*fmt)
            {
                *str++ = *fmt;
            }
            else
            {
                --fmt;
            }
            continue;
        }

        if (qualifier == 'l')
        {
            num = va_arg(args, unsigned long);
        }
        else if (qualifier == 'h')
        {
            if (flags & SIGN)
            {
                num = va_arg(args, short);
            }
            else
            {
                num = va_arg(args, unsigned short);
            }
        }
        else if (flags & SIGN)
        {
            num = va_arg(args, int);
        }
        else
        {
            num = va_arg(args, unsigned int);
        }

        str = number(str, num, base, field_width, precision, flags);
    }

    *str = '\0';
    return str - buf;
}

int sprintf(char *buf, const char *fmt, ...)
{
    va_list args;
    int n;

    va_start(args, fmt);
    n = vsprintf(buf, fmt, args);
    va_end(args);

    return n;
}
